Frequently, parents and physicians will be concerned about a child with a "lazy eye." This is a common catch-all term, yet it can have various meanings, with different treatment implications. It can refer to a droopy lid (ptosis), an eye that is misaligned (strabismus), or an eye with poor vision (amblyopia) that appears normal.

At Cottage Children's Hospital, we have successful treatment options available to correct these common causes of vision impairment.

Ptosis

Ptosis is among the more obvious causes of a "lazy eye." Congenital ptosis is often due to poor development of the levator palpebrae muscle in the upper lid. Why is ptosis important in childhood? Primarily because an eye with a droopy lid is at risk for vision loss due to blockage of the upper visual field.

Mark Silverberg, MD

Most notably, if the lid is obscuring the pupil, the risk of vision loss is increased. However, even without pupil blockage, there can be a threat to vision. An eye with ptosis is more prone to astigmatism as the droopy upper lid induces warping of the cornea. Children with ptosis may require glasses to correct astigmatism and/or surgical correction to elevate the lid. When surgery is required, a "sling" procedure is used to link the dysfunctional upper lid to the properly functioning frontalis. Frequently, children will require a second surgery later in childhood as the linkage ultimately wanes over time. However, the key is to clear the visual axis early in life so that proper vision can develop.

Ptosis can lead to vision loss due to blockage of the upper visual field or astigmatism.

Strabismus

Among the more common deviations found with strabismus are esotropia (eye going in) and exotropia (eye going out). Some children with esotropia will have high underlying hyperopia (far-sightedness) and require glasses to improve their alignment (accommodative esotropia), while others are more than likely to require surgical correction (infantile esotropia). Patching the "good" eye can also be used in some cases.

Children with exotropia may be managed initially with exercises and/or patching, although strabismus surgery is often required as well. Strabismus surgery involves recession (loosening) or resection (tightening) of involved muscles. Results are generally immediate and gratifying, although some patients may need more than one surgery.

Esotropia may be corrected with glasses or require surgery.

Exotropia also often needs to be corrected through surgery.

Amblyopia

The third, and less obvious, condition is amblyopia. This is the most common cause of vision impairment in childhood. While an eye might appear to be perfectly normal, it can still have profound vision loss. How is this possible? If one eye has a significantly different refractive error, the brain will start to favor the "good" eye and ignore the "bad" eye. Over time, the eye with the higher refractive error will gradually and almost imperceptibly lose vision. Children with this condition will not complain or display signs of poor vision because they are able to rely on their "good" eye for daily activities.

Amblyopia, a condition in which the eye appears to be perfectly normal, can lead to severe vision loss.

Screening for amblyopia in the primary care office is vital, as detection is the key first step. Once an amblyopic eye is identified, it can usually be treated with glasses, patching or atropine eye drops. After the age of 7 or 8 years, a child with amblyopia is more difficult to treat, so early detection and treatment are essential.